The present disclosure relates to methods and apparatuses for forming a concentric winding coil, and more particularly to methods and apparatuses for forming a concentric winding coil in which a coil end portion protruding from an axial end face of a stator core has a plurality of different nonlinear shapes, from a rectangular conductor wound in a predetermined plurality of turns.
Conventionally, methods and apparatuses for forming a stator coil in which a coil end portion protruding from an axial end face of a stator core has a plurality of different nonlinear shapes are known in the art (see, e.g., JP 2012-239371 A). In the forming apparatus of Patent Document 1 includes a holding mechanism that holds therein a rectangular conductor having a quadrilateral section, a die that bends the rectangular conductor of a predetermined length held in the holding mechanism so that the rectangular conductor can be used as a stator coil, and a moving mechanism that causes the die to make a stroke movement toward the holding mechanism. In such a forming apparatus, when the moving mechanism causes the die to make a stroke movement toward the holding mechanism, the rectangular conductor of the predetermined length held in the holding mechanism is bent so that a corresponding portion corresponding to the coil end portion of the stator coil is formed into a crank shape, an arc shape, and a bent shape. A single-layer stator coil in which crank formation, arc formation, and edgewise formation have been performed on the coil end portion is formed by such a bending process.